Dados do Trabalho

Título

USEFULNESS OF RAMAN SPECTROSCOPY AND LIPID ANALYSIS OF DECOMPOSED HUMAN BONES IN FORENSIC GENETICS AND MOLECULAR TAPHONOMY

Introdução

Molecular taphonomy studies the transformation of biomolecules after death, of which DNA is considered the most informative. For over 30 years, DNA analysis of postmortem bones has allowed the identification of decomposed human bodies, since they are most likely to be recovered. However, DNA analysis of postmortem bone is technically challenging. Therefore, new methods for DNA screening have been extensively studied. RS is a potential screening tool due to its ability to monitor organic and inorganic components, minimally destructive, time- and cost-efficient nature. In the same sense, GC/MS analysis of bone lipids has never been performed in forensics nor archaeoanthropology with that scope.

Objetivos

To assess biomarkers in forensic human bones that might be associated with DNA using Raman Spectroscopy and GC/MS.

Parte experimental

Femoral diaphysis samples were collected from 50 decomposing corpses found in Mato Grosso, Brazil, with diverse burial environments, causes of death, and PMIs (6 to 13 years). Methods employed are detailed on Table 1.

Table 1. Description of methods employed.
Analysis Technique Target
Human DNA Real-time PCR 67 bp; 180 bp
STR genotyping PCR/CE 16 STRs + Amel
Physicochemical RS Molecular bonds
Lipid GC/MS Total lipids

Resultados e Discussões

We hypothesize FAMEs are formed during bone putrefaction, where microbial activity is high. Bacterial release of methanol, gases, and other by-products results in pH changes and high internal pressure, which could promote the reaction between free fatty acids and methanol. Statistically significant associations observed are presented on Table 2.

Table 2. Significant associations observed.
Variable Associated with p-value
v1PO43- position 180 bp human DNA 0.0371
Methyl hexadecenoate STRs detected 0.0424

Conclusões

RS and GC/MS may be useful in molecular taphonomy and forensic genetics studies.

Referências e agradecimentos

UNAL, Mustafa et al. Compositional assessment of bone by Raman spectroscopy. Analyst, v. 146, n. 24, p. 7464-7490, 2021.
EDSON, Suni et al. Determination of materials present in skeletonized human remains and the associated DNA: Development of a GC/MS protocol. FSI: Synergy. v. 1, p. 170-184, 2019.

Palavras Chave

Forensic genetics, bones, DNA, Raman spectroscopy, gas chromatography/ mass spectrometry.

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